An image forming apparatus such as a copy machine, MFP (multifunction peripheral) or printer may form an image on coated papers as well as ordinary copy papers. If the coating material of coated papers has a glass transition point similar to that of a developer including toner, coated papers stacked after an image is formed thereon may stick to each other.
A conventional image forming apparatus reduces the print speed in the case of forming an image on a coated paper (see, for example, JP-A-2005-202166). Therefore, there is a problem that the number of print sheets per unit time with respect to coated papers is lowered.